What's the worst that can happen? (And, how can we protect ourselves?)

[Karen M.]

This is a spin off of another thread where we discussed risk, risk avoidance, risk management, and getting over the fears of getting started.   

Question:  What's the worst that can happen to a real estate investor?  And, how do we protect / prevent each of the worst case scenarios? 

Brainstorm your "worsts" -- let's figure out our protections.  Thanks!   Back later to fill in.